From the industry “experts” I’ve heard from and worked with, the answer is yes there will be a world with many less regional jets. However that does not mean you should expect to see large aircraft operating on small routes, it means those routes will disappear. With the current trend, it is predicted by 2020 many cities and airports will lose service, especially those that do not and can not sustain service of at least 100 seat aircraft.
Just a year ago Delta pulled out of 24 communities, many of which had been served by Northwest through Mesaba for many years. Some found new service through Great Lakes Airlines, or even American Eagle in a few cities, but a few others are still waiting to find a replacement, even with the Essential Air Service program. Even then, that program is constantly just one congressional vote away from being eliminated.